Pneumatic press



June 17, 1969 R. P. LICKLITER T AL 5 PNEUMATIC PRESS Filed Dec. 27. 1966Sheet of s I NV E NTOR. R69? PLzbZz'tEv: Edi-[0 50f anJJBZu 1?]?eeuesATTORNEYS".

June 17, 1969 R. P. LICKLITER ET AL 3,450,037

PNEUMATIC PRESS Filed Dec. 27, 1966 Sheet 3 of3 INVENTOR.

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June 17, 1969 R. p. LICKUTER ET AL 3,450,037

PNEUMATIC PRESS 70% I 1' NVENTOR.

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United States Patent US. Cl. 100-256 12 Claims ABSTRACT OF THEDISCLOSURE The press has a pneumatically operated piston and cylindermounted between a height adjustable upper plate and a ram plate fordriving the latter downwardly on guideposts into a die set area againstresilient, height adjustable, stops whereby the ram plate reboundsupwardly to assist the spring retraction thereof. The piston facecarries resilient stops which, together with the die set area stops,reduce the noise at both ends of the ram plate stroke. A heightadjustable control switch is actuated by the ram plate before the end ofthe downstroke to stop inflow of air into the cylinder.

Background of the invention The present invention relates to a fluidactuated press and in particular to a pneumatic press actuated by apiston and cylinder mounted between a ram plate and an upper plate andhaving a mechanical assist for returning the ram plate.

Conventional presses include a ram head mounted for vertical slidingmovement on a plurality of vertical guideposts upstanding from astationary bed, the ram head and stationary bed defining a die set areatherebetween. An upper plate is usually secured to the upper ends of theguideposts to maintain the latter in vertical alinement therebypermitting free sliding movement of the ram plate. In certain instances,the ram head is fluid actuated by a piston and cylinder arrangementlocated above the upper plate with a piston rod extending therethroughto drive the ram head downwardly into the die set area, the ram headbeing mechanically returned by springs or the like. Inaccuracies inalinement and resulting reduction in efliciency are introduced in thesearrangements necessitating relatively high fluid operating pressures andheavy return springs. Moreover, lagging and inconsistent ram headresponse to its actuating control signal occurs in these presses wherebypress set-up time is increased and variations in work in the die setarea introduced. An unacceptable noise level is also created due, in alarge measure, to stopping the direction of the ram head at both ends ofits stroke.

Summary of the invention It is a primary object of the present inventionto provide a pneumatic press having a piston and cylinder operable atlow pressures and arranged between the upper plate and the ram head todirectly drive the latter.

It is another object of the present invention to provide a pneumaticpress having a mechanical assist providing an initial upward thrust toreturn the ram head at the end of its downstroke.

It is still another object of the present invention to provide apneumatic press having a piston and cylinder drive arrangement whereinfluid flow into the cylinder is cut off prior to the end of the ram headdownstroke.

It is yet another object of the present invention to provide a pneumaticpress having a ram head engageable against height adjustable stops tolimit its downstroke and wherein such stops react to return the ramhead.

It is a further object of the present invention to provide a pneumaticpress having a quick response to press actuating control signals wherebyvariations in work in the die set area is substantially eliminated.

It is yet a further object of the present invention to provide apneumatic press having the foregoing characteristics which isconstructed to reduce noise to a minimum, and wherein the shut heightcan be easily and readily adjusted.

In one aspect thereof, a pneumatic press constructed in accordance withthe principles of the present invention is characterized by a bed plate,a plurality of vertically eX- tending guide posts fixed at their lowerends to the bed plate, an upper plate carried on the guide postsadjacent the upper ends thereof and adjustable vertically to selectivelyvary its height above the bed plate, a ram plate vertically slidable onthe guide posts and defining a die set area with the bed plate, meansfor urging the ram plate downwardly toward the bed plate including apiston and cylinder disposed between the upper plate and the ram plate,together with a valve for supplying air under pressure into thecylinder, a plurality of resiliently deformable stops carried by the bedplate to limit downward movement of ram plate and provide an initialupward return thrust to the ram plate at the end of its downstroke andspring means suspending the ram plate from the upper plate forcompleting the return of the ram plate.

The foregoing and other objects, advantages and characterizing featuresof the air actuated press of the present invention are pointed out indetail in the following description of a typical embodiment thereofconsidered in conjunction with the accompanying drawings depicting thesame wherein like numerals represent like parts throughout the variousviews.

Brief description of the drawings FIG. 1 is an elevational view of oneform of a pneumatic press constructed in accordance with the presentinvention;

FIG. 2 is a cross-sectional view thereof taken about on line 22 of FIG.1;

FIG. 3 is a fragmentary, enlarged, cross-sectional view of the pistonand cylinder arrangement utilized therein;

FIG. 4 is a horizontal, cross-sectional view of the press taken about online 4-4 of FIG. 2; and

FIG. 5 is a schematic illustration of a control circuit for use with thepneumatic press.

Detailed description of a preferred embodiment The drawings show oneform of pneumatic press constructed in accordance with the principles ofthe present invention comprising a stationary bed 10, a plurality ofvertically extending guideposts 11 suitably fixed at their lower ends tobed 10, a ram head plate 12 vertically slidable on guideposts 11 anddefining a die set area 13 with bed 10, and an upper plate 14 slidablyadjustable on guideposts 11. A plurality of upstanding threaded posts 15are threaded at their lower ends into bed 10 and extend upwardly throughopenings in ram plate 12 and upper plate 14, the latter being securedadjacent the upper ends of posts 15, between nuts 16 to adjustably fixthe height of upper plate 14 above bed 10. Bed 10 and plates 12 and 14are preferably rectangular in plan form, and can be formed of steelplating with the bores in plates 12 and 14 receiving guideposts 11 eachhaving the shank portion of a guide bushing 17 fixed therein in aconventional manner. Track members 18 and 19 are suitably secured on theundersurface of ram plate 12 and on the upper surface of bed plate 10,respectively and are adapted to receive the upper and lower dies of theusual die set, not shown. Of course, it will be appreciated that thepress of this invention is of general utility, and is not limited to usewith die sets.

Ram plate 12 s suspended below upper plate 14 by a ram plate returnassembly comprising, in the illustrated form, eight rods 20 suitablyfixed at their lower ends to ram plate 12 and passing upwardly throughopenings in upper plate 14. The upper end of each rod 20 mounts a washer21, a nut 22 and a lock nut 23 and a compression spring 24 encircleseach rod 20 with its opposite ends bearing against washer 21 and theupper surface of upper plate 14. Ram plate 12 is thus resilientlysupported for reciprocating sliding movement on guideposts 11 by springs24 with downward movement thereof into die set area 13 being against thebias of springs 24 and limited by a plurality of stops 26 verticallyadjustably mounted on rods between ram plate 12 and bed plate 10. Stops26 comprise sleeves 27 threaded on rods 15 and fixed in verticallyadjusted position by jam nuts 28 engaging against their undersurfaces.The upper surface of each sleeve 27 has a resiliently deformable cushion29 preferably formed of rubber, glued or otherwise fixed thereon forlimiting downward movement or ram plate 12 and providing a noiselessinitial return thrust to ram plate 12 at the end of its downstroke.

It is a significant feature hereof that with the foregoing arrangementthe shut height is easily adjusted by moving nuts 16 to adjust theheight of upper plate 14 which thereby adjusts the height of ram plate12 since the latter is solely supported by the ram plate return assembly-24. Moreover, since stops 26 are adjustably mounted on rods 15 it willbe seen that variations in height of the adjustable spacing betweenplate 12 and stops 26 can be provided relative to bed plate 10.

A pneumatically actuated piston and cylinder arrangement is disposedbetween upper plate 14 and ram plate 12 to drive the latter downwardlyinto die set area 13. A cylinder 31 is suitably secured to theundersurface of upper plate 14 interiorly of guideposts 11, posts 15 androds 20 as by bolts 32 (FIGS. 2 and 4) and is provided with a suitableO-ring seal 33 (FIG. 3) sealing against upper plate 14. A piston 34 issuitably secured to the upper surface of ram plate 12 in verticalregistry with cylinder 31 as by bolts 35 and dowels 36 (FIG. 4) and isformed of a heavy material providing considerable inertia to ram plate12 during its downstroke. As illustrated in FIG. 3, the upper edge ofpiston 34 has a pair of peripheral flanges 37 having a suitable O-ringseal 38 carried therebetween for sealing against the inner surface ofcylinder 31.

The upper surface of piston 34 is slightly cylindrically recessed as at39 providing a narrow lip 40 about its periphery, recess 39 and lip 40defining a working chamber 41 with upper plate 14. It will beappreciated that the diameter of piston 34 is very near the lateraldimension of ram plate 12 providing a very large and substantial area onthe upper surface of piston 34 against which air entering cylinder 31,as hereinafter described, can react whereby low pressure air can providea considerable downward force. Also, the large lateral dimension of thepiston and cylinder arrangement and the direct connection thereof to theram and upper plates respectively maintain ram plate 12 in accuratevertical slidable registry on guideposts 11 without undue frictiontherebetween.

A plurality of cylindrical cavities 42 are formed in the recessessurface of piston 34 for receiving resilient deform-able cushions 43,preferably formed of rubber. Cushions 43 extend upwardly slightly beyondlip 40 to engage against the undersurface of upper plate 14 at the endof the piston upstroke whereby metal to metal contact between piston 34and upper plate 14 is avoided and consequent noise therefrom eliminated.

Upper plate 14 is centrally bored to threadably receive the lower end ofan air conduit 46 connecting at its up per end to a three way air valve47. An air reservoir comprising an accumulator tank 48 communicates viapipe line 49 with an air source, not shown, which can be a conventionalindustrial air supply, and with air valve 47 via a conduit 50 to provideair under constant pressure through valve 47 into chamber 41 for drivingram plate 12 downwardly. The end of conduit 50 terminates above thebottom of tank 48 as shown in FIG. 1, to prevent accumulated condensateor sediment from communicating into and fouling valve 47. Air valve 47has an exhaust conduit, not shown and can be any conventional solenoidpilot operated, spring return, three-way valve.

A valve control switch 55 is suitably mounted on upper plate 14 andpositioned vertically below a switch actuating arm 56 carried by athreaded rod 57. Rod 57 is threaded at its lower end into a suitableopening in ram plate 12 and is fixed thereto by a jam nut 58. Rod 57passes upwardly through an opening in upper plate 14 and carriesactuating arm 56 above upper plate 14 in vertically adjustable positionbetween a pair of nuts '60 whereby arm 56 can be adjusted to depressbutton 59 and actuate switch 55 immediately prior tothe end of thepiston downstroke. Switch 55 controls valve 47 to cut off the air supplyto cylinder 31 whereby the timed relation between switch '55 and the endof the Piston downstroke reduces press vibration and provides sulficienttime for valve 47 to shift to exhaust thereby preeluding piston returnagainst air pressure remaining in cylinder 31.

In FIG. 5, there is schematically illustrated an energizing circuitincluding switch 55 for shifting air valve 47 between positionsestablishing air communication between tank 48 and cylinder 41 fordriving piston 34 downwardly and exhausting the air in cylinder 31.Power is provided from suitable source, not shown, via leads 60 and 61.Spring biased, normally open contacts 62 of latching relay 63 are closedby energization of coil 64 via leads 60 and 65, normally closed contacts66, 67 of a command switch 68, lead 69, coil 64, and leads 70 and 61.Command switch 68 may be a conventional single pole double throw switch,the switch herein having a switch operator 71 spring biased to anormally closed position with contact 67.

Command switch 68 is actuated by work passing through the die set area13 into abutment with switch operator 7'1 to close a circuit throughcontacts 66 and 72 and open the circuit through contacts 66 and 67,whereby coil 64 is deenergized. Contacts 62 are held closed, however, bya latch 73 operated by a latching coil 74, latch 73 latching contacts 62closed immediately upon the closing thereof via coil 64. Closingcontacts 66 and 7.2 completes an energizing circuit to solenoid 75 ofair valve 47 to shift the latter into position providing air underpressure from tank 48 into working chamber 39 to drive ram plate 34downwardly, the energizing circuit comprising leads 60 and 65, contacts66 and 72, lead 76, contacts 62, lead 77, solenoid 75 and leads 78 and61.

Near the end of the downstroke of piston 34, actuating arm 56 depressesbutton 59 to close normally open switch 55 and complete an energizingcircuit for latching coil 74 via leads 60 and 79, switch 55, lead 80,coil 74 and leads 70 and 61, to release latch 73 and thereby allowcontacts 62 to open. Opening of contacts 62 interrupts the energizingcircuit for solenoid 75 and valve 47 is shifted by its spring return toexhaust air from cylinder 31.

Air flow from tank 48 into cylinder 31 is thus interrupted and springreturn assembly 20-24 and cushioned stops 26 act to return ram plate 12.Return of ram plate 12 opens switch 55 and command switch 68 isthereafter automatically reset upon removal of the work to reestablishthe energizing circuit hereinbefore described through contacts 66 and 67whereby contacts 62 are again, closed and the air press is cocked readyfor another downstroke. Air can thus be provided into cylinder 31substantially instantaneously with actuation of switch 68 whereby lag inram plate response is substantially eliminated.

Thus it is apparent that the objects of my invention have been fullyaccomplished. Direct driving force is applied to the ram plated due tothe mounting of the piston and cylinder on and between the ram and upperplates respectively. Low air pressure can be used due to the largelateral dimensions of the cylinder. Lighter springs are utilized toreturn the ram plate since an initial return thrust is provided by therebound effect of the ram plate against stop cushions 29, thus furtherreducing the air pressure required to drive the ram plate downwardlyagainst the bias of springs 24. Noise at either end of the stroke issubstantially eliminated and vibration greatly reduced by the provisionof the rubber cushions 29 and 43. Cutting off the air supply to thepneumatic cylinder prior to the end of the downstroke reduces pressvibration and provides sufiicient time for valve 47 to shift whereby thereturn stroke does not operate against air pressure in cylinder 3-1.Switch button 59 has suflicient travel to accommodate closure of switch55 prior to the end of the power stroke.

Having thus described and illustrated a preferred embodiment of ourinvention, it will be understood that such description and illustrationis by way of example only and that such modifications and changes as maysuggest themselves to those skilled in the art are intended to fallwithin the scope of the present invention as limited only by theappended claims.

What we claim as new is:

1. In an air actuated press, a bed, a plurality of upright guidepostsfixed at their lower ends to said bed, an upper plate engaging saidguideposts adjacent the upper ends thereof, means mounting said upperplate for vertical adjustment to selectively vary the height thereofabove said bed, a ram plate vertically slidable on said guideposts anddefining a die set area with said bed, pneumatically operated means forurging said ram plate downwardly toward said bed including a piston andcylinder disposed between said upper plate and said ram plate, valvemeans operable to supply air under pressure into said cylinder and toexhaust the same, a plurality of resiliently deformable stops positionedto limit downward movement of said ram plate and provide an initialupward return thrust thereto at the end of the downstroke thereof, andspring means suspending said ram plate from said upper plate forcompleting the return of said ram plate, wherein said cylinder isdirectly mounted on the undersurface of said upper plate and said pistonis directly mounted on the upper surface of said ram plate in verticalregistry with said cylinder, the lateral dimension of said piston beingvery near the lateral dimension of said ram plate thereby providing alarge piston surface area against which air under pressure introducedinto said cylinder can react.

2. An air press according to claim 1 said mounting means including aplurality of upright rods fixed at their lower ends to said bed andextending upwardly through said ram plate and said upper plate, andmeans releasably clamping said upper plate in vertically adjustedposition along said rods.

3. An air press according to claim 1 including means mounting said stopson said bed, said stops being vertically adjustable relative to saidbed.

4. An air press according to claim 1 including resilient means disposedbetween said upper plate and said ram plate for cushioning said ramplate at the end of its upstroke.

5. An air press according to claim 4, said resilient means being carriedon the face of said piston and engageable against the undersurface ofsaid upper plate.

6. In an air actuated press, a bed, a plurality of upright guidepostsfixed at their lower ends to said bed, an upper plate engaging saidguideposts adjacent the upper ends thereof, means mounting said upperplate for vertical adjustment to selectively vary the height thereofabove said bed, a ram plate vertically slidable on said guideposts anddefining a die set area with said bed, pneumatically operated means forurging said ram plate downwardly toward said bed including a piston andcylinder disposed between said upper plate and said ram plate, valvemeans operable to supply air under pressure into said cylinder and toexhaust the same, a plurality of resiliently deformable stops positionedto limit downward movement of said ram plate and provide an initialupward return thrust thereto at the end of the downstroke thereof, andspring means suspending said ram plate from said upper plate forcompleting the return of said ram plate, including means responsive to apredetermined downward movement of said ram plate and controlling saidvalve means to interrupt the supply of air into said cylinder, whereinsaid control means includes a switch mounted on said upper plate, and aswitch actuator carried by said ram plate and extending above saidswitch whereby downward movement of said ram plate carries said actuatorinto engagement with said switch to actuate the same, wherein saidactuator includes a rod carried by said ram plate and extending upwardlyabove said upper plate, and an arm carried by said rod above saidswitch, together with means mounting said arm on said rod for verticaladjustment therealong, thereby to vary the point in said downstroke atwhich said switch is actuated.

7. An air press according to claim 6 said mounting means including aplurality of upright rods fixed at their lower ends to said bed andextending upwardly through said ram plate and said upper plate, meansreleasably securing said upper plate in vertically adjusted position onsaid rods above said bed, means mounting said stops on said rods forvertical adjustment therealong, said cylinder being directly mounted onthe undersurface of said upper plate and said piston being directlymounted on the upper surface of said ram plate in registry with saidcylinder, and resilient cushions carried on the face of said piston andengageable against the undersurface of said upper plate.

3. In an air actuated press, a bed, a plurality of upright guidepostsfixed at their lower ends to said bed, an upper plate engaging saidguideposts adjacent the upper ends thereof, means mounting said upperplate for vertical adjustment to selectively vary the height thereofabove said bed, a ram plate vertically slidable on said guide-posts anddefining a die set area with said bed, pneumatically operated means forurging said ram plate downwardly toward said bed including a piston andcylinder disposed between said upper plate and said ram plate, valvemeans operable to supply air under pressure into said cylinder and toexhaust the same, a plurality of resiliently deformable stops positionedto limit downward movement of said ram plate and provide an initialupward return thrust thereto at the end of the downstroke thereof, andspring means suspending said ram plate from said upper plate forcompleting the return of said ram plate, wherein said cylinder isdirectly mounted on the undersurface of said upper plate and said pistonis directly mounted on the upper surface of said ram plate in verticalregistry with said cylinder, and means responsive to a predetermineddownward movement of said ram plate and controlling said valve means tointerrupt the supply of air into said cylinder prior to the end of saiddownstroke and before said ram plate engages said stops.

9. An air press according to claim 8 wherein said con trol meansincludes a switch mounted on said upper plate, and a switch actuatorcarried by said ram plate and extending above said switch wherebydownward movement of said ram plate carries said actuator intoengagement with said switch to actuate the same.

10. In an air actuated press, bed means, upper plate means, a pluralityof guideposts extending from said bed means toward said upper platemeans, ram plate means slidable on said guideposts between said upperplate means and said bed means, a plurality of rods extending from saidbed means toward said upper plate means, means releasably clamping saidupper plate means in vertically adjusted position along said rods,pneumatically operated means for urging said ram plate means toward saidbed means including a cylinder directly mounted on the undersurface ofsaid upper plate means and a piston movable in said cylinder anddirectly mounted on the upper surface of said ram plate means, valvemeans operable to supply air under pressure into said cylinder and toexhaust the same, a plurality of resiliently deformable stops mounted onsaid rods for vertical adjustment therealong, said stops beingpositioned to limit movement of said ram plate means toward said bedmeans and provide an initial return thrust thereto, and spring means forcompleting the return of said ram plate means.

1'1. In an air actuated press, bed means, a plurality of guidepostsextending upwardly from said bed means, upper plate means, ram platemeans vertically slidable on said guideposts between said upper platemeans and said bed means, means releasably securing said upper platemeans in vertically adjusted position, pneumatically operated means forurging said ram plate means downwardly toward said bed means including acylinder directly mounted on the undersurface of said upper plate meansand a piston movable in said cylinder and directly mounted on the uppersurface of said ram plate means, valve means operable to supply airunder pressure into said cylinder and to exhaust the same, resilientlyyieldable cushion means positioned for engagement by said ram platemeans upon predetermined downward movement thereof, and return springmeans for said ram plate means.

12. An air press according to claim 11, the lateral dimension of saidpiston being very near the lateral dimension of said ram plate therebyproviding a large piston surface area against which air under pressureintroduced into said cylinder can react.

References Cited UNITED STATES PATENTS 633,665 9/1899 Spaulding 100266XR 2,072,694 3/ 1937 Walter. 2,406,403 8/ 1946 Roger, 2,726,707 12/1955Wellons et al. 2,786,409 3/ 1957 Claire 100266 2,938,232 5/ 1960 Martin.3,024,720 3/1962 Welsh 100266 XR 3,190,215 6/1965 Howard et a1. 1002573,194,096 7/1965 Comet 83588 XR 3,329,068 7/1967 Klaus 9285 XR 3,333,4478/1967 Alspaugh.

BILLY J. WILHITE, Primary Examiner.

US. Cl. X.R. 72-445, 453; 83529, 588; 92-85; 100257, 266, 269

